title: Iridium-coated micropore x-ray optics using dry etching of a silicon wafer and atomic layer deposition.
abstract: To enhance x-ray reflectivity of silicon micropore optics using dry etching of silicon (111) wafers, iridium coating is tested by use of atomic layer deposition. An iridium layer is successfully formed on sidewalls of tiny micropores with a pore width of 20 μm and depth of 300 μm. The film thickness is ∼20  nm. An enhanced x-ray reflectivity compared to that of silicon is confirmed at Ti Kα4.51 keV, for what we believe to be the first time, with this type of optics. Some discrepancies from a theoretical reflectivity curve of iridium-coated silicon are noticed at small incident angles <1.3°. When a geometrical shadowing effect due to occultation by a ridge existing on the sidewalls is taken into account, the observed reflectivity becomes well represented by the modified theoretical curve. An estimated surface micro roughness of ∼1  nm rms is consistent with atomic force microscope measurements of the sidewalls.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ogawa
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Ezoe
authors.forename: Teppei
authors.initials: T
authors.lastname: Moriyama
authors.forename: Ikuyuki
authors.initials: I
authors.lastname: Mitsuishi
authors.forename: Takuya
authors.initials: T
authors.lastname: Kakiuchi
authors.forename: Takaya
authors.initials: T
authors.lastname: Ohashi
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Mitsuda
authors.forename: Matti
authors.initials: M
authors.lastname: Putkonen